The aim of these experiments was to test whether the developmental potential of nuclei from intestinal epithelial cells of Xenopus laevis tadpoles declined during the life of the functional larval gut. The results of transplantation of nuclei from three different stages of development were compared: stages 46-48, when feeding begins and while yolk is still present but before the formation of th...

1. Methylxanthines (IBMX, caffeine, theophylline), which are known inhibitors of c-AMP phosphodiesterase inhibited reversibly progesterone-induced maturation of Xenopus oocyte. 2. The time course of protein phosphorylation during maturation stimulated by progesterone was analysed in Xenopus oocyte : protein phosphorylation increased around germinal vesicle breakdown (GVBD). No quantitative chan...

BACKGROUND The tumor suppressor p53 plays a key role in regulating the cell cycle and apoptosis in differentiated cells. Mutant mice lacking functional p53 develop normally but die from multiple neoplasms shortly after birth. There have been hints that p53 is involved in morphogenesis, but given the relatively normal development of p53 null mice, the significance of these data has been difficul...

BACKGROUND The origin recognition complex (ORC) and the minichromosome maintenance (MCM) protein complex were initially discovered in yeast and shown to be essential for DNA replication. Homologues of ORC and MCM proteins exist in higher eukaryotes, including Xenopus. The Xenopus MCM proteins and the Xenopus homologues of Saccharomyces cerevisiae Orc 1p and Orc2p (XOrc1 and XOrc2) have recently...

Oct-1 and a second, previously unidentified octamer-binding protein (Oct-R) have been identified in extracts of Xenopus laevis oocytes and embryos. Oct-1 does not bind to the octamer motif associated with certain Xenopus laevis histone H2B gene promoters, whereas Oct-R binds well to this motif, but only in the sequence context of the H2B gene promoter.

Transmission electron microscopy has been used to study the chromosomes found in the early diplotene oocytes of Xenopus laevis. Chromosomes from 40 micron early diplotene oocytes were found to possess a normal lampbrush chromosome morphology. The contour length of the loops found on these chromosomes was measured, the mean value determined and compared with that for lampbrush chromosomes found ...

Abstract In plants high affinity transport proteins mediate the essential of ammonium across membranes. Arabidopsis thaliana six these AMmonium Transporters (AMTs) are encoded by genome. All them show a unique expression pattern. While most AMTs highly expressed in root, AtAMT1;4 is limited to pollen grains and tube. Here, we addressed characteristics heterologous Xenopus laevis oocytes system....

BACKGROUND The African clawed frogs Xenopus laevis and Xenopus tropicalis are prominent animal model organisms. Xenopus research contributes to the understanding of genetic, developmental and molecular mechanisms underlying human disease. The Xenopus Anatomy Ontology (XAO) reflects the anatomy and embryological development of Xenopus. The XAO provides consistent terminology that can be applied ...

(6-4) photolyase is a flavoenzyme that catalyzes the chemically challenging repair of carcinogenic photoproduct lesions in DNA using sunlight. Nature may have overcome challenge by combining two distinct successive photoreactions, each starting with electron transfer from an excited flavin to lesion. We herewith report transient absorption study returns following chemical transformations succes...